Microbial Growth And Ecology

Microbial Growth And Ecology

Microbial Growth EXAM 3Highlighted questions are from articles1Distinguish between macronutrients and micronutrientsMacronutrients elementsnutrients required in large amountsMicronutrientselementsnutrients required in small amounts2Give at least 6 examples of macronutrientsMacrocarbon oxygen nitrogen hydrogen sulfur phosphate3Give at least 4 examples of micronutrientsMicrosodium potassium calcium magnesium4How do growth factors differ from macronutrients and micronutrientsThey are both necessary for the cell but they are needed in very different amounts 5Name the 5 groups describing an organisms relationship to oxygenObligate aerobesonly do aerobic respiration need oxygen Obligate anaerobesonly do anaerobic respirationfermentationpoisoned by oxygen Facultative aerobescan do aerobic respiration in the presence of oxygen but can also ferment or respire anaerobically Microaerophilesneed oxygen to respire but poisoned in high concentrations dont need high pressure Aerotolerant anaerobescant use oxygen metabolically but can grow in oxic environment because oxygen does not poison them 6What type of broth can be used to determine an organisms oxygen requirementWhat does this broth contain that makes it possible to determine an organisms oxygen requirementThioglycolate brothiThioglycolate is a reducing agent reacts with oxygen to form water used to remove oxygen from broththe oxygen is only present at the air interface 7You inoculate the following organisms into tubes containing thioglycolate brothWhere would you expect to see growth in the tubeObligate aerobetop of tube all in oxygen area Obligate anaerobebottom away from oxygen poisoned by oFacultative aerobemost in oxic some dispersed evenly through anoxic bc aerobic makes more atp than without oxygenMicroaerophilesome in oxic area some in anoxic towards the top near oxygen need oxygen but poisoned by high concentrations of oxygen Aerotolerate anaerobedispersed evenly throughout tube not poisoned by oxygen8What accommodations need to be made to grow an aerobe in the labYou have to have exposure to air shaking to get cells dispersed in environment bubbling of sterile air 9What accommodations need to be made to grow an anaerobe in the labNo air exposure to organisms you can fill it up completely so there is no air left and sealed you could use a reducing agent staph or thioglycolate you can use anoxic jar boxes to make an anoxic environment etc harder to grow anaerobe10During what process are toxic oxygen molecules generatedByproducts in respiration11How does an organism protect themselves from toxic oxygen moleculesEnzymes that break down toxic oxygen forms into something they can useiCatalase peroxidase superoxide dismutase superoxide dismutasecatalase combination superoxide reductase12What enzyme combinations would detoxify superoxide OIn what organisms might 2those combinations be foundSuperoxide dismutase and it can be combined withiCatalaseobligate aerobes facultative aerobesiiReductaseobligate anaerobes 13Where can an organism get nitrogenAtmospheric nitrogen N2 or fixing nitrogen from inorganic compounds such as ammonia NH3 and nitrate NO314Name a molecule that requires phosphorusWhere can a cell get phosphorusObtained from free phosphates and phosphate mineralsNeeded to make nucleic acids and phospholipids15Name a molecule that requires sulfurWhere can a cell get sulfurObtained from sulfates so4 or sulfides Needed to make amino acids cysteine and methionine and other vitamins ironsulfur proteins16Name a molecule that requires potassiumWhere can a cell get potassiumObtained from free K or K saltsNeeded to make some enzymes used to maintain solute concentration17Name a molecule that requires magnesiumWhere can a cell get magnesiumObtained from salts in various minerals